Mobile devices, such as hearing assistance devices, typically include digital electronics to enhance the user's experience. The power source for many mobile devices is selected to be light and small, yet to provide adequate power for a predictable duration. This is especially true for hearing aids, where the size and weight of the power source have a significant effect on the size and comfort in using the hearing aid.
There is a desire to provide an indication of the remaining battery life for hearing aid batteries. This is especially true because of the widespread use of smartphones or sophisticated hearing aid remotes that can connect wirelessly to hearing aids. However, hearing aid batteries (e.g., zinc-air batteries) exhibit voltage and impedance levels that may remain nearly constant over the majority of the life of the battery. Often the only way to test a hearing aid battery is to attempt to use the hearing aid to determine if the battery is working or dead.
What is needed in the art is an improved method of identifying battery state and battery capacity.